Ni—P／纳米TiO2化学复合镀研究

在Ni—P酸性化学镀镀液中加入TiO2纳米颗粒，以Ni—P最佳工艺为基础，采用三因素二水平正交实验的方法获得优化的Ni—P／TiO2复合镀层。利用扫描电镜（SEM）、X射线衍射仪（XaD）对镀层的表面形貌和微观结构进行观察。结果表明：Ni～P／TiO2复合镀层中的Ni—P镀层包裹着少量纳米颗粒，但纳米颗粒团聚现象明显，大部分沉积在镀层表面。同时，Ni—P／TiO2复合镀层在不同温度的热处理后，由于非晶态的Ni—P镀层中复合了高硬度TiO2纳米颗粒，从而增强了镀层的抗局部变形能力和弥散强化的效果，而且也强化了Ni—P合金基体，使得其显微硬度性能都得到了一定程度的提高。此外，Ni—P／TiO2复合镀层由于TiO2纳米颗粒加入，使复合镀层孔隙率和界面增加，从而使其耐腐蚀性略有降低。

Effect of microstructure and properties adding Nano-TiO2 particle in Ni-pchemical coating

Adding nanometer-sized TiO2 particle in acid solution of Ni-P electroless plating ,in base of the optimum formula of Ni-P electroless plating, ideal composite coating of Ni-P/TiO2 was obtained by using orthogonal experimental method in two factors and three levels,surface micrograph and microstructure of the composite coating was observed by using SEM,TEM and XRD,the results show that Ni-P coating contain small quantities nano-TiO2 particles in Ni-P/TiO2 composite coating, most nano-TiO2 particles stay at surface bcacause of its congolation. Meanwhile, because amorphous state Ni-P coating compound nanometer-sized TiO： particles, the abiiity of fight local distortion and dispersion strengthening was strengthened,and base material of Ni-P also was consolidated,so microhardness of the Ni-P/TiO2 composite coating was made better by the different terperature heating. Furthermore, because amorphous state Ni-P coating compound nanometer-sized TiO2 particles,the compositive coating increase in porosity and interface,so corrosion resistance of the Ni-P/TiO2 composite coating reduce.